Cloud storage is a model of networked online storage where data are stored on multiple virtual servers, generally hosted by third parties. There are several advantages with cloud storage. For example, by storing data on remote servers instead of on one's own user devices (i.e., clients), the storage space on the user devices may be freed up for other uses. At the same time, the data may be professionally managed by the third parties (e.g., organize, backup, secure, etc.) and easily shared with other people.
Online storage has become popular in recent years as the amount of digital data grows rapidly. In one instance, many social-networking websites provide various forms of online storage to their users in order to support and encourage information sharing among the users. For example, Flickr® (www.flickr.com) is a web-based service that enables its users to upload and share digital images; and YouTube (www.youtube.com) is another web-based service that enables its users to upload and share digital videos and audios.